For something literally so small, nanotechnology has gained an awful lot of intrigue in recent years. Definitions vary, but a basic working definition of nanotechnology is the “engineering of functional systems at the molecular level,” according to the Center for Responsible Nanotechnology (CRN). While applications are often applied to the scientific realm – organic chemistry, molecular biology, physics, etc. – its role in the nonwovens industry continues to pick up steam.

The National Nanotechnology Initiative (NNI), an organization that expedites the discovery, development and deployment of nanotechnology, puts the science’s dimensions between approximately one and 100 nanometers, and states that it’s “where unique phenomena enable novel applications.”Our industry can draw upon what NNI says can be achieved through this science: “Most benefits of nanotechnology depend on the fact that it is possible to tailor the essential structures of materials at the nanoscale to achieve specific properties, thus greatly extending the well-used toolkits of materials science. Using nanotechnology, materials can effectively be made stronger, lighter, more durable, more reactive, more sieve-like, or better electrical conductors, among many other traits. There already exist over 800 everyday commercial products that rely on nanoscale materials and processes.”

Nonwovens applications can include nanoscale additives or surface treatments of fabrics that help resist wrinkling, staining and bacterial growth, and provide lightweight ballistic energy deflection in personal body armor. Also, nano-engineered materials can make superior household products, such as degreasers and stain removers, environmental sensors, alert systems, air purifiers and filters.

While there is much talk within the industry about what nanotechnology can do, actual applications are still limited. But the same cannot be said about research. Several universities and companies are making significant investments and great strides, and are excited about finding out potentially where this technology can go.

Forcespinning and the Cyclone
Roger Lipton, senior vice president sales and marketing, FibeRio Technology, McAllen, TX, USA, addresses the status of the market, and what he describes is its puzzling nature. He says, “The nanofiber market has captured the interest of the world’s leading companies in markets ranging from hygiene and filtration to medical devices, transportation, energy and defense. The enigma surrounding nanofibers is the question:“Why are these multinational companies focused on such a small market?”

The served nanofiber market in 2010, according to BCC research, is only around $140 million, but is projected to grow to $2 billion by 2020. Tipton says the management team at FibeRio believes this interest is driven by potential – the potential to dramatically improve the functionality of a wide range of materials, offering competitive advantages to those bold enough to pursue nanofiber solutions.

The answer, Lipton says, is quite simple. “Nanofiber production technology has not caught up with demand and applications,” he says. So why is the market so small? Lipton says it’s due in part to the fact that these incredible super-high surface area structures have been relegated to niche products, with high price tags due to low volume, and high-cost production technologies. “Most applications are not benefitting from the various physical characteristics manifested by nanofibers such as extreme strength, hydrophobicity, hydrophilicity, softness, low porosity and slip flow effect highly desired in filtration media,” he says.

FibeRio’s Vision Statement is in direct response to this unmet demand: “To transform the materials market through the unlimited availability of nanofibers.” To realize its vision, FibeRio has developed its Forcespinning technology that both has “expanded the range of materials that can be processed into nanofibers, as well as increased productivity by orders of magnitude while decreasing operating expenses versus other technologies,” Lipton says.

Forcespinning is based on a centrifugal force to process polymeric and ceramic materials, mechanically, into the nanoscale. By using only centrifugal force, Forcespinning works equally well with solutions or pure molten materials. It uses less solvent or no solvent at all so it is much more cost effective than electrospinning. Also, it does not use any external heated air jets, making it cheaper than meltblown.Industrial scale systems can be installed as either standalone, or in-line continuous process systems.

Most recently, FibeRio has launched the Cyclone FE 1.1, officially unveiled in Chicago at the Filtration 2011 International Conference and Exposition organized by INDA. The new Cyclone is able to produce nanofibers with diameters averaging 500 nanometers and below, with a very tight standard distribution that ensures uniform slip flow, barrier or absorption, among other properties and features a proprietary design that uniformly deposits the nanofibers across its 1.1-meter width. Raw material is fed to the machine via an advanced extrusion and solution pump system that can be controlled discretely or by software custom-designed to interface with the customer’s factory floor controls.

“Over the past year we have received an outstanding response to our technology and equipment, with the largest nonwovens and filtration companies in the world asking us to provide them with equipment that will expand the market for nanofiber functionalized media through new materials and lowered cost,” adds Ellery Buchanan, CEO, FibeRio. “The Cyclone FE 1.1 has unparalleled output capacity and eliminates the requirement for toxic solvents making it the perfect manufacturing platform to spread across multiple business units. Nonwovens and filtration companies can now proceed rapidly to establish a secure, competitive position. It is a very exciting time for FibeRio and the nonwovens industry at large.”

Catch the NanoWave
Hollingsworth & Vose, East Walpole, MA, is another company that’s made great strides in not only R&D, but also in developing commercial applications.

Angelika Mayman, director of business development for H&V, discusses nanotechnology’s growth and its penetration in the industry. She says, “Many players have emerged offering nanofiber materials – roll goods producers, toll producers, equipment suppliers and fiber suppliers, and participants are coming from all parts of the supply chain.”

Mayman, however, notes that because no common platform exists just yet, nonwoven product development is happening simultaneously with process development.

And size matters, Mayman adds. “While smaller is not always better for all applications, due to increasing requirements for higher efficiency and lower energy use, the trend within some segments is towards smaller fibers with greater overall surface area.”

H&V has an established position in nanofiber technology – ranging from glass to synthetic to composite materials. “Glass fiber media for HEPA and ULPA applications have been using nanofibers for decades, Mayman explains. “This media combines surface and depth filtration properties. Glass fiber media of this kind have a very high specific surface which is a major advantages for cleanroom applications and IAQ improvement.”

H&V has numerous nanotechnology-based products that are commercially available. For example, the company offers Nanoweb for air and liquid filtration, which is H&V’s advanced nanofiber technology that offers submicron efficiency, low pressure drop and high performance against soot. It is available as a standalone web or a coating on nearly any substrate.

NanoWave for commercial HVAC systems is another offering. “NanoWave is a synthetic alternative to glass mat media that offers increased sustainability and high discharge efficiency. Produced with a single-polymer, the media’s stiff design results in enhanced processability and creates rigid pockets for filters,”Mayman says.“With low pressure drop and high dust-holding capacity, the media fits a broad range of HVAC applications. Charged NanoWave is also offered, which provides increased submicron particle retention, as well as higher MERV classifications.”

Working within the nanotechnology space – because it’s so new – presents a unique set of challenges, as it’s yet to be determined the effects it may have on people.

“Removal of nano-particles is perceived as a challenge for the future as their effect on humans is not understood,” Mayman explains. “Protecting humans from exposure to nano-particles is being investigated. However there are strong indications that high performing microglass media perform for nano-particles.

“Many end users in the market believe that simply adding a nanofiber layer to existing materials will offer a significant advantage. It is the optimized combination of nanofiber materials and the base layer which can provide an advantage as there are many factors to consider including compatibility of the materials, adhesion of one layer to another, and choice of nanofiber diameter. H&V is well-positioned to offer optimized material composites.”

Research and development
Companies like FibeRio and Hollingworth & Vose have made some serious inroads. But also spearheading the charge are leading universities.

Recent research at the Nonwovens & Advanced Materials Laboratory, Texas Tech University (TTU) is focused on developing cotton nanofiber composites with enhanced filtration capabilities. Seshadri Ramkumar and Vinitkumar Singh, Nonwovens & Advanced Materials Laboratory, TTU, say that recent results show that aerosol filtration efficiency of nanofiber embedded cotton fabric is almost doubled when compared with untreated cotton fabric. “Of course, the durability of such nanofibers layers is still an issue as it is the weak van Der Wall force that is holding the layers onto the base substrates. To overcome this, it is convenient to use one or several layers of nanofibers between base substrates as a sandwich. Donaldson Company has developed such products for filtration and it is common practice these days in the industry to use nanofibers in sandwiched structures,” Ramkumar says.

Ramkumar also points to the work being conducted by Xungai Wang, professor and director of the Center for Material and Fiber Innovation, Deakin University in Australia. He says Wang has been working to develop novel materials using nanotechnology.

“According to Professor Wang, a new form of solvent spinning has been invented and patented by his group. In this patented technology, a metallic disc is used to produce electrospun nanofibers instead of syringes. Uniform fiber distribution, higher production capability, simple operating procedure and simplified machinery give this technology an edge over other solvent based electrospining techniques,” Ramkumar says.

So the academic community is taking on the nano-challenge with R&D designed to help develop products. But Ramkumar emphasizes that another important challenge for the nano sector is to thoroughly understand the environmental and health risks associated with nanotechnology-based products.

Closing the gap
It’s been said that some people fear what they don’t understand, and this sentiment can apply to nanotechnology. Last month, the European Commission published a definition of nanomaterials, a move that will help regulators identify whether such ultra-fine particles – whose risks are still largely unknown –are present in certain consumer goods.

The definition will allow EU regulators to draw up a list of products that contain nanomaterials in order to carry out risk assessments, though products would remain on the market while analysis was carried out, an EU official said.

The Commission's definition of nanomaterials included particles between one and 100 nanometers in diameter. Around three hundred million particles each 100 nanometers wide could fit onto the head of a pin.

European Environment Commissioner Janez Potonik says: "I am happy to say that the EU is the first to come forward with a cross-cutting designation of nanomaterials to be used for all regulatory purposes. We have come up with a solid definition based on scientific input and a broad consultation. Industry needs a clear coherent regulatory framework in this important economic sector, and consumers deserve accurate information about these substances. It is an important step towards addressing any possible risks for the environment and human health, while ensuring that this new technology can live up to its potential.”

European consumer organization BEUC, however, takes issue with the commission’s definition, saying that products containing nanomaterials should be proven safe before being allowed onto the EU market.“There is a knowledge gap, but for the moment people are being exposed to nano products,” adds Monique Goyens, director general of BEUC.

Nanoparticles behave differently to larger particles and can be easily inhaled through the lungs and enter the blood stream and blood cells, notes Peter Gehr, a professor at the Institute of Anatomy at the University of Berne and head of a steering group on the opportunities and risks of nanomaterials. “Nanoparticles have been found inside human organs such as the brain, nose, lungs, skin and gastrointestinal tract, but their impact once inside these organs is not yet clear,” Gehr says.

And some experts have said manufacturers could be reluctant to use nanomaterials in their products, due to fears of a similar consumer backlash that greeted genetically modified foods in Europe.

Goyens argues that companies have in the past said that their products are safe before scientific research later proved otherwise, citing examples such as asbestos. “They (industry) want to maximize profits,” she says.

Certain environmental campaigners complained that the Commission's definition was too narrow, and many products would avoid EU risk assessment as a result.

“The European Environmental Bureau (EEB) is deeply disappointed by the Commission’s decision to use a narrow definition for the term ‘nanomaterial,’ indicating that industry lobbying has won over the Commission’s own scientific advisors,” the EEB said in a statement.

The textile industry heretofore has focused on two aspects of nanotechnology: fibers and finishes. The issues surrounding the commercialization and applications of nanofibers are well known to the industry, and they include productivity, performance related characteristics, scale-up and cost. There have been a few developments in the recent past to overcome these aforementioned issues. In addition, it is not clear whether the nanotechnology-enabled products meet with the consumer expectations with regard to the need for the low-cost-in-volume based commodity textiles sector.

Nanotechnology based textile materials can be broadly classified into non-functional textile products and functionalized/finished textiles. Nano textiles are basically textile structures of nano size such as nanofibers and other fibrous structures. These basic structures can be built-up further to develop higher order structures such as fabrics and composites where nanofibers and other fibrous structures can serve as building blocks. The inherent characteristics of these nanomaterials such as high surface area and weight-to-volume ratio at the building block level will be of great advantage wherever high performance, life and environmental related end uses are involved. In our view, the cost of such nano enhanced products will not be an issue in health care, environment, defense, aerospace and advanced technology sectors. Furthermore, because of the dependence of the nano sector on high level research and development and IP protection, developed economies such as the U.S., Europe, Israel, Australia and Canada will have an edge at least until 2030. In addition, because of the nature of the nanotechnology industry in terms of the technology and its size, it gives immense opportunities for small and medium sized enterprises to venture into this field. We endeavor to provide a new – albeit simple – method of classifying nanofibers based on the dispersion process by which they are produced.